1. Field of the Invention
The present disclosure describes a novel flame retardant and fire extinguishing product for preventing and fighting fires in liquids.
2. Description of the Related Art
There are two general methods of reducing the potential damage from the burning of combustible materials—preventive treatment and active firefighting. Preventive treatment with a flame retardant may reduce the flammability of a material. Once a material begins to burn, the fire may be extinguished with an appropriate mix of fire retardants and fire extinguishing agents in liquid, solid, or gaseous form.
The use of flame retardants not only reduces the risk of a fire starting but also hinders its propagation. This increases the available time to escape from the damage and thus protects humans, property, and the environment.
An ideal flame retardant or fire extinguishing agent will have the following properties: (1) it will significantly reduce the flammability of the materials to which it is applied; (2) it will significantly reduce the risk of re-ignition after a material to which it is applied is exposed to fire conditions; (3) it will be non-toxic to humans, animals, and plants; (4) it will be biodegradable or at least not harmful to the environment; (5) it will not cause the release of toxic or corrosive substances under extreme fire conditions; (6) it will not migrate from the materials to which it is applied via evaporation or other forms of release; (7) it will not negatively affect the recyclability of materials to which it is applied; and (8) its production, processing, application, and disposal or recycling will not cause significant environmental harms.
Numerous fire extinguishing agents are available for actively fighting fires in liquids. A limited number of available agents may also be used preventatively to increase the fire resistance of liquids. Various shortcomings of currently available agents for retarding and fighting fires in liquids are described hereinafter.
Currently available fire extinguishing agents used to fight fires in liquids present several shortcomings: (1) secondary damage caused by use of the fire extinguishing agent; (2) re-ignition risks; (3) short-term or long-term toxicity and environmental damage; and (4) lack of general utility based on limitation to use for specific types of fires.
Water, the most common fire extinguishing agent for extinguishing fires in solid materials, cannot be used to extinguish fires in many liquids. When water is applied to a burning liquid that is immiscible with water, the less dense of the two liquids will form the top layer. Many common flammable liquids such as gasoline, kerosene, and many oils are both immiscible with and less dense than water. If water is applied to a burning liquid with these properties, the burning liquid will form the top layer. The water will then be heated by the burning liquid to form steam, and then it will cause the burning liquid to be sprayed in all directions and thereby cause the fire to spread. To use water to extinguish a fire in a burning liquid with these properties, it must be mixed with a foam-forming material or another similar substance. Even when water can be used to extinguish a fire in a liquid, it presents shortcomings. Using water creates the risk of vapor explosion when fighting fires in enclosed spaces due to the presence of high temperature steam. Using water to fight a fire in a liquid may also result in contamination of large amounts of water with pollutants, which will then be spread into the environment.
Carbon dioxide is an effective fire extinguishing agent for certain types of fires. It does not leave any residue and is relatively inert. However, toxic concentrations of carbon dioxide are generally required to fight large fires. In addition, carbon dioxide dissipates rapidly and thus it is not an effective agent for smoldering fires or preventing re-ignition. It can also damage certain electronics.
A variety of foams also are used to fight fires in liquids. Fire extinguishing foams are generally used to cool fires and to coat burning liquids to prevent contact with oxygen, thereby suppressing combustion. The type of foam used to fight a specific fire depends on various factors, including the size of the area affected by fire, whether the affected area is an enclosed or open space, and the properties of the burning liquid(s). Specialized foams are used to fight fires in liquids comprising oxygenates and polar liquids, as such liquids may degrade many fire extinguishing foams not specifically designed to be inert to such liquids. These specialized foams are often described as alcohol-resistant foams.1 Ethanol fires typically require highly specialized foams which are correspondingly very expensive. 1 See, e.g., http://www.fomtec.com/foam/category33.html
Many foams used to fight fires in liquids are toxic, generate toxic byproducts, or are otherwise harmful to the environment.2 Non-toxic alternatives generally are restricted in their uses, have a limited lifespan, or present other shortcomings. The use of foams often requires expensive clean-up operations after completing the firefighting. The foam often must be applied so as to achieve full coverage of the ignited materials to effectively extinguish the fire. Many foams are limited to use for fighting only specific types of fires. Moreover, fire extinguishing foams are often non-adhesive to many liquids, and thus the foam may be blown off the previously covered liquid by wind or be dispersed by the natural flow of the liquid, leading to re-ignition. Preventing re-ignition of extinguished surfaces will reduce the response times when a fire occurs, reduce risks to firefighters, increase opportunities to save lives endangered by fire, and increase opportunities to protect property at risk for damage or destruction by fire. 2 http://www.haifire.com/Resources/publications/Environmental_Impacts_of_Firefighting_Foams.pdf
Most of the currently available agents for fighting fires in liquids can only extinguish fires and cannot be used for preventative treatment. Many available agents are toxic, generate toxic byproducts, or are otherwise harmful to the environment. In addition, many available agents are specialized and can only be used to fight certain types of fires. Ethanol fires are particularly difficult to extinguish using currently developed fire extinguishing agents in common use, and often require highly specialized fire extinguishing agents developed specifically for ethanol fires. Re-ignition is also a significant problem not adequately addressed by currently available fire extinguishing agents.
While some fire extinguishing agents, such as certain types of fire extinguishing foams, can also be used preventatively to retard fires in liquids in certain circumstances, these uses present the same shortcomings as use of the same agents in active firefighting.
Thus there remains a need for environmentally safe, effective flame retarding and fire extinguishing agents which can be used to prevent and fight a variety of types of fires in liquids and which effectively prevent re-ignition upon use.